Non-contacting roll cleaning device



N 7, 6 H. w. HEISTERKAMP NONCONTACTING ROLL CLEANING DEVICE 2Sheets-Sheet 1 Filed Dec. 26, 1963 INVENTOR. fer/02250 f/frfieri w WedsM 9mm Nov. 7, 1967 H. w. HEISTERKAMP nouconnc'rmc, ROLL CLEANING DEVICE2 Sheets-Sheet 2 Filed Dec. 26, 1963 buy United States Patent 3,351,039NON-CONTACTING ROLL CLEANING DEVICE Herbert W. Heisterkamp, Cleveland,Ohio, assignor to The Dow Chemical Company, Midland, Mich, a corporationof Delaware Filed Dec. 26, 1963, Ser. No. 333,523 4 Claims. (Cl. 118-70)This invention relates to a non-contacting roll cleaning device, and amethod for cleaning a sheet coating roll.

In the coating of certain sheet materials, such as with a latexsolution, the coating is applied in a quantity greater than thedesiredcoating thickness. This is done to insure full or adequatecoverage over the entire sheet width. The coated sheet is then carriedover a backing, or breast roll, where proper coating weight is achievedby the knifing action of an air jet. The excess coating material, whichis sheared off to a collecting pan below, forms a dam directly below thecontacting line of the air jet on the breast roll. The dam inevitablycarries over the edges of the sheet with the result that the exposedbreast roll is coated with the coating material which is knifed to athickness approximating that on the film.

The coating on the roll partially dries due to an exposure which resultsin a gradual but continuous buildup of coating material adjacent eachedge of the sheet being coated. This has at least two detrimentaleffects:

(1) The continuously wetted build-up is edged by the sheet but someinward flow along the roll may occur at the unwrapped portion on thebreast roll. This allows coating material to flow underneath the sheetin uneven and perhaps heavy globs. Aside from drying problems, itpresents problems in obtaining a good roll with the need for edge trim.

(2) The build-up continues until it reaches a depth equal to the gapbetween the air knife and the roll. Subsequently, contact with the airknife takes place, and debris in the form of small, dried particles ofcoating material, is sheared off and carried into the coating materialpan, or directly onto the coated web, which adversely affects thequality of the coated web.

The apparatus of the subject invention corrects the foregoing coatingproblem. Briefly, the inventive concept involves the production of anegative, wetting atmosphere adjacent the edges of the sheet beingcoated. The ambient atmospheric pressure will cause a lifting of thewetted coating material on the roll adjacent the edges of the sheet,which lifted material will be conducted to a drain. In such manner, thedanger of contamination of the coating material or the sheet beingcoated, is avoided. The apparatus which may be utilized to effect therealization of the inventive concept, does so in a simple and elfectivemanner, and without physical contact with the roll being cleaned, thusavoiding any scratching, or marring thereof.

The main object of this invention is to provide a noncontacting rollcleaning device.

A more specific object is to provide a non-contacting roll cleaningdevice which is effective to remove residual coating material from aroll at each edge of a sheet being coated.

These and further objects and features of the invention will become moreapparent from the following description and accompanying drawingswherein:

FIG. 1 is a plan view of apparatus embodying the principles of theinvention;

FIG. 2 is a side view of the same;

FIG. 3 is a plan view, on a reduced scale, of the apparatus of FIG. 1 asoperatively mounted upon a roll;

FIG. 4 is a section view generally as seen along line 4-4 in FIG. 1;

FIG. 5 is a section view 5-5 in FIG. 1; and

FIG. 6 is a section view 66 in FIG. 1.

Referring now to the drawings, a pair of cap, or cup elements 10 arepositioned above a breast roll 12, as used in web coating apparatus, sothat a curved peripheral edge of a lower open end 14 is maintained ashort distance, such as 0.010", above the surface of the breast roll, asbest seen in FIG. 4. The cup elements 10, which may be made of anon-metalic substance, such as Teflon, to avoid scratching the breastroll in event of contact therewith, are positioned so that the centerlines thereof would coincide with the edges of a sheet of film 16 (FIG.3). A manifold block 18 is positioned midway between the cups 10, saidblock being secured by pipes 20, 22, 24 and 26 Which conduct water andair to and from the cups, as will be described in greater detailhereinafter. Pipes 20 and 22 straddle one of the cups 10, while pipes 24and 26 straddle the other cup 10; a disc 28 is arranged for clamping therespective pipes on each cup so that the cups are maintained inoperative position. Cap bolts 30 are provided for securing the discs 28in position on the cups. It will be seen that the disc clampingarrangement will allow a lateral shifting of the cups 10 so that theymay be adjusted to accommodate Whatever width of film is beingprocessed. Means (not shown) are provided for fixing the ends of thepipes 20, 22, 24 and 26.

Each cup 10 has a tapered recess 32 into which an air nozzle 34protrudes in axial alignment with a pipe nipple 36 having a bell mouthinlet radius 38. The nozzle 34 and the pipe nipples 36 provide a venturieffect whereby the kinetic pressure of inlet air under compressionflowing from the nozzle 34, is converted to static pressure whichovercomes the flow friction in the discharge pipes 24 and 26. An axiallyarranged water inlet pipe 40 extends downwardly in the closed end ofeach cup 10 through a recess 42, the lower end of each pipe 40 being inspaced relation to an orifice 44. An annular opening is thus providedfor egress of compressed air. A passageway 46 is formed in each cup toconduct compressed air from the nozzle 34 to the recess 42. In suchmanner, air flowing out of the orifice 44, will mix with water flowingfrom the lower end of the pipe 40 to create a fog, or mist, within eachcup recess 32.

The end of pipe 20 is threaded in a recess 48 in the manifold block 18,which recess serves hose, or tubing 50 adapted to conduct compressed airto the nozzle 34 of each cup 10. The end of pipe 22 is threaded in arecess 52 in the manifold block -18, which recess serves hose, or tubing54 adapted to conduct. water to the inlet pipe 40 of each cup 10.

An exhaust tubing, or hose, 56 is connected at one end to each pipenipple 36, said tubing being connected at the other end to a recess 58formed in the manifold block 18. In such manner, the fluid and airmixture in each cup recess 32 is carried to a drain, together with anyweb coating debris, or residual entrapped therein, by Way of the pipes24 and 26.

Operation of the above described apparatus is as follows. Compressedair, at approximately 30 p.s.i., is discharged through each nozzle 34while water is conducted to the inlet pipe 40. The pressure of the wateris not important. However, since the best fogging occurs with slightnegative water pressure, it is preferred that water be conducted toinlet pipe 40 at a pressure slightly below that of the air emergingthrough the annular orifice 44 so that this air causes the induction ofthe water into recess 32 as a fog. Under such circumstance, it issubstantially self regulating by its own design. Since a moist, negativeatmosphere is maintained in each cup 10, sufiigenerally as seen alongline generally as seen along line cient Wetting of the coating materialon the roll 12 is effected. Also, since the cup 10 has a sub-atmosphericpressure within its recess 32, the outside atmospheric pressure causesan air flow into the cup to carry residual coating material into thecup. Then, by reason of the fog within the recess, there is a dilutionof such residual coating material so that it is discharged throughtubing 56. Obviously, sufiicient water must be introduced through nozzle44 to insure adequate dilution of the coating material picked up so asto keep tubing 56 clear.

From the foregoing it will be seen that the apparatus described willsatisfy all of the objectives of the in- Vention.

The foregoing description has been given in detail without thought oflimitation since the inventive principles involved are capable ofassuming other forms without departing from the spirit of the inventionor the scope of the following claims.

What is claimed is:

1. In combination with web coating apparatus including a roll over whicha web is passed after having a coating material applied thereto andmeans cooperating with said roll to provide a uniform thickness of thecoating material across the width of the web, the improvement comprisinga non-contacting roll cleaning device for re moving residual coatingmaterial on the roll on each edge of the web, said roll cleaning deviceincluding a pair of cup elements, each having an open end in uniformperipheral spaced relation to the surface of said roll, a liquid inletmeans for admitting a liquid into the cup, an air inlet nozzleprojecting into the cup, an air receiving pipe in spaced relation 'tosaid nozzle and in axial alignment therewith, passageway means arrangedto conduct air from the nozzle to the liquid inlet means for mixing withliquid delivered into the cup to create fog conditions in the cup, andmeans for conducting fluid material from within said cup elements to adrain.

2. A non-contacting roll cleaning device, as claimed in claim 1, whereinsaid air receiving pipe has a bell mouth inner end whereby a venturieffect is created by air flow coming from the nozzle and entering thereceiving plpe.

3. A non-contacting roll cleaning device, as claimed in claim 2, furtherincluding a manifold block positioned between the cup elements, rigidpipe means for positionally maintaining the manifold block and the cupelements, and for delivering compressed air and water to the manifoldblock, hose means extending between the manifold block and each cupelement for delivering compressed air to the cup elements, an exhausthose means extending between each cup element and the manifold block forconducting fluid material from within said cup element to a drain.

4. A non-contacting roll cleaning device, as claimed in claim 3, whereinsaid cup elements are laterally adjustable relative to each other.

References Cited UNITED STATES PATENTS 2,135,406 11/1938 MacDonald118-63 2,899,339 8/1959 Rakus 118-63 3,141,203 7/1964 Whitehurst et al.15256.51 3,149,005 9/1964 Brundige 118-104 FOREIGN PATENTS 585,84710/1959 Canada.

MORRIS O. WOLK, Primary Examiner.

G. R. MYERS, Assistant Examiner.

1. IN COMBINATION WITH WEB COATING APPARATUS INCLUDING A ROLL OVER WHICHA WEB IS PASSED AFTER HAVING A COATING MATERIAL APPLIED THERETO ANDMEANS COOPERATING WITH SAID ROLL TO PROVIDE A UNIFORM THICKNESS OF THECOATING MATERIAL ACROSS THE WIDTH OF THE WEB, THE IMPROVEMENT COMPRISINGA NON-CONTACTING ROLL CLEANING DEVICE FOR REMOVING RESIDUAL COATINGMATERIAL ON THE ROLL ON EACH EDGE OF THE WEB, SAID ROLL CLEANING DEVICEINCLUDING A PAIR OF CUP ELEMENTS, EACH HAVING AN OPEN END IN UNIFORMPERIPERAL SPACED RELATION TO THE SURFACE OF SAID ROLL, A LIQUID INLETMEANS FOR ADMITTING A LIQUID INTO THE CUP, AN AIR INLET NOZZLEPROJECTING INTO THE CUP, AN AIR RECEIVING PIPE IN SPACED RELATION TOSAID NOZZLE AND IN AXIAL ALIGNMENT THEREWITH, PASSAGEWAY MEANS ARRANGEDTO CONDUCT AIR FROM THE NOZZLE TO THE LIQUID INLET MEANS FOR MIXING WITHLIQUID DELIVERED INTO THE CUP TO CREATE FOG CONDITIONS IN THE CUP, ANDMEANS FOR CONDUCTING FLUID MATERIAL FROM WITHIN SAID CUP ELEMENTS TO ADRAIN.